On Monday, he tweeted out a much more extreme prediction: “Probably closer to 2030 to 2040 imo,” he wrote. “2060 would be a linear extrapolation, but progress is exponential.”

This forecast puts him more in the camp of radical intellectuals like Ray Kurzweil; exponential progress is the logic behind the singularity, a concept that Kurzweil and others describe as the point at which innovation occurs so dramatically that human existence is completely unrecognizable before and after.

Musk has long been preoccupied with the idea of an inevitable A.I.-dominated future, and thinks it would be a “dangerous situation.” This anxiety inspired him to create the startup Neuralink, which aims to merge the minds of humans and machines so that people can keep apace with A.I.’s rapid advancement. Basically, Musk wants to avoid becoming a slave of robots. Seems reasonable.

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Of course, Musk also has many critics who don’t think that his mechanized-brain dream will be possible. Noam Chomsky, for one, argues that since we don’t even fully understand what a thought is, biologically-speaking, we certainly can’t replicate one with technology.

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It’s hard to say whether Musk understands the future more than most of us do, or whether he’s just paranoid. But there’s something to be said for taking no chances, and if a humans-versus-robots battle erupts, he’ll be among the best prepared.